Hydroxy-1&#39;.8&#39;-naphthoylene-naphthimidazoles



Patented July 12, 1932 UNITED STATES PORATION OF DELAWARE PATENT OFFICE WILHELM EEIIMEIER AND WILHELM MEISER, 0F LEVERKUSEN ON-THE-RHIN'E, GER- MANY, ASSIGNORS TO GENERAL ANILINE WORKS INCL, OF NEW YORK, N. Y., A COR- HYDROXY-1.8-N.APHTHOYLENE-NAPHTHIMIDAZOLES No Drawing. Application 'filed July 19, 1929, Serial No. 379,573, and in Germany July 23, 1928.

as i.

wherein n stands for one of the numbers one and two and wherein the naphthalene nuclei may be further substituted.

These starting compounds are obtainable according to the process described by Bistrzycki and Risi, Helvetica chimica acta 1925,

volume 8, page 818 by condensing in a suitable solvent a naphthalicacid anhydride or a derivative thereof with an 1.2-naphthy lene-diamino sulfonic acid.

Our new process proceeds very smoothly, and after a short time, say about hour, the reaction is complete. On neutralizing the alkali melt obtained accordingto our process with a mineral acid, the new compounds separate in the form of their alkali metal salts; the free naphthols are obtainable by the addition of a mineral acid. They are generally yellowish to orange colored substances of a high melting point, ditficulty soluble in organic solvents if they are free from a sulfonic acid group, butnot melting and insoluble in organic solvents if they contain a sulfonic acid group. The new compounds are valuable intermediate products in the manufacture'of dye'stufi's and pharmaceutical sub stances. '1 y The following examples will illustrate our invention, without limiting it thereto; the

parts are by weight: I

Ewample 1.The 1 .8-naphthoylene-a-1.2- naphthimidazole-6-sulfonic acid, obtainable from 1.Q-naphthylenediamine-5-sulfonic acid by condensation with naphthalic acid anhydride (nomenclature according to Richter, Lexikon der Kohlenstofiverbindungen, 8rd edition, page 21), is fused at 250 C. with 7 parts of caustic potash and some water. After neutralizing the bulk of the alkali with mineral acid the naphtholate separates. It is converted into the free naphthol by acids. The new compound having the formula:

crystallizes from pyridine in the form of ordissolves with difiiculty in glacial acetic acid andis rather difiicultly soluble in osdichlorobenzene and nitrobenzene. It has the following structural formula:

Emample 2.-The 1' .8 -naphthoylene-a-1.2'- naphthimidazole-6.8-disulfonic acid, obtainable from LZ-naphthylenediamine 5fl disulfonic acid by condensation with naphthalic acid anhydride, is fused with 6 parts of caustic potash and 2.5- parts of water at ISO-190 C; From 'the diluted melt the orange colored, diflicultly soluble l.8.-naphthoylene-a- 1.2 -'naphthimi dazole 6- hydroxy 8 sulfonic acid of the formula: V

V 7 V I V HO B\/ p H separates on acidification.

In an analogous manner the 1'. 8--nap-hthoylene-a-1.2-naphthimidazole-7.9-disulfonacid anhydride) yields the orange colored, w

ic a-cid (obtainable from 1.2-naphthylenediamine-6.8-disulfonic acid and naphthalic difficulty soluble 1C8 naphthoylene oz 1.2-

naphthilnidazole-9-hydroxy-7-sulfonic acid. It has the following structural formula:.

Example e-The 3'- or G sulfOnic acid- 1, 8-naphthoylene-o-1.2-naphthimidazole 6- sulfonic acid, obtainable by condensing naphthalic acid anhydride 3esulfonic acid and 1.2-

naphthylene-diamine-5-sulfonic acid, is fused at 250 C. with 7 parts of caustic soda; From the diluted melt'there separates on acidifying with a mineral acid the 6-hydroxy-3" or 6-hydr0Xy-1';8'-naphthoylene-a-1.2-naphthimidazole. From pyridine it is obtained in the form of orange colored needles which are not yet molten at 355 C. It corresponds to one of the following formulae:

Ewample 4.-4e or 5-hydroxy-1 .8 -naphthoylene-a-1.2-naphthimidazole 6 --sulfonic acid, obtainable by condensing LQ-naphthyL enediamine-5-sulfonic acid and ,ehydroxynaphthalic acid anhydride, is fused'at 250 C. with 7 parts of caustic potash. From the diluted melt there separates on acidifying with mineral acid the 6 -hydroxy-4- or 5-hydroxy-l .8 -naphthoylene-a- 1.2-naphthimid azole, which corresponds to one of the fol lowing formulae: 7

When recrystallized from pyridine it is obtained in the form of orange colored crystals which are not yet molten at 855 C.

We claim:

1. As new products, the compounds of the general formula:

of i

wherein y stands for hydrogen or the sulfonic acid group and wherein the naphthalene nuclei may be further substituted by a hydroxy group, said compounds being generally yellowish to orange colored sub stances, having a high melting point or melting not at all, difiicultly soluble or insoluble in organic solvents'and being valuable intermediate products in the manufacture of dyestuffs and pharmaceutical substances.

2. As new products, the compounds of the general formula:

wherein one an stands for a hydroxy group, the other as stands for hydrogen, y stands for hydrogen or the sulfonic acid group, and wherein the naphthalene nuclei may be further substituted by a hydroxy group, said compounds being generally yellowish to orsaid compound being an orange colored substance melting at 328 (1., difiicultly soluble in organic solvents and being a valuable intermediate product in the manufacture of dyestuffs and pharmaceutical substances.

4. As a new product, the compound of the formula:

said compound being an orange colored substance, difiicultly soluble in organic solvents and being a valuable intermediate product in the manufacture of dyestuffs and pharmaceutical substances.

5. As a new product, the compound of the formula:

said compound crystallizing from pyridine in the form of orange colored needles, melting at 350 0., being difiicultly soluble in organic solvents and being a valu-ablerintermediate product in the manufacture of dyestuffs and pharmaceutical substances.

In testimony whereof we have hereunto set our hands.

WILHELM NEELMEIER.

[1,. s] WILHELM MEISER. [n s] 

